Complex systems, in particular, open complex giant systems have become one of major challenges to many current disciplines such as system sciences, cognitive sciences, intelligence sciences, computer sciences, and information sciences. An appropriate methodology for dealing with them is the theory of qualitative-to-quantitative metasynthesis. From the perspective of engineering, we propose the concept of metasynthetic computing. This paper discusses the theoretical framework, problem-solving process and intelligence emergence of metasynthetic computing from both engineering and cognition perspectives. These efforts can help one understand complex systems and design effective problem-solving systems.